The purpose of this study is to explore the professional practices of teachers in both a Positive Behavior Support (PBS) high school and a traditional high school using Charlotte Danielson's (1996) 22 components of teaching responsibility that are clustered into four domains: Domain 1: Planning and Preparation, Domain 2: Classroom Environment, Domain 3: Instruction, and Domain 4: Professional Responsibilities. This comparison serves as a tool to determine if there is any difference in the professional practices of teachers in a high school with Positive Behavior Support and those in a traditional school. The results may be used to examine a variety of means to provide effective staff development and possible PBS implementation strategies. The teacher professional practices data retrieved were attained from teachers and principals of PBS and non-PBS schools. The major views that came forward from the respondents' survey questionnaires demonstrated that teachers and principals from the two schools characterize their professional practices quite similarly. Results from this study confirm the findings of research studies discussed in the literature review. On the whole, there were many similarities in the characterizations and levels of importance of teacher professional practices in the PBS and non-PBS schools. The descriptive data displayed that the PBS school out performed the non-PBS in the majority of the identified student outcomes. This study also noted that effective leadership and staff training are needed to facilitate the implementation of school improvement tools, such as PBS. / Ed. D.